A microcracks-induced damage model for initially anisotropic rocks accounting for microcracks closure

Séverine Levasseur (1) , Hélène Welemane (2) , Djimédo Kondo (3)

1 Departement Architecture, Géologie, Environnement et Constructions - ArGEnCo (Liège, Belgium)
2 LGP - Laboratoire Génie de Production
3 DALEMBERT - Institut Jean Le Rond d'Alembert

We formulate a new micromechanical damage model for anisotropic rocks. This model accounts not only for the coupling between material initial anisotropy and the damage-induced one, but also for the opening/closure status (the so-called unilateral effects) of evolving microcracks. A closed-form expression of the overall free energy of the microcracked medium is implemented in an appropriate thermodynamics framework to derive a complete damage model for initially anisotropic rocks. The salient features of this model are fully illustrated. Then, its capabilities are demonstrated through an application to a Taiwan argillite subjected to direct tensile loading (including off-axis ones) for which the damage model well captures experimental data (mechanical response, growing damage rocks strength). Finally, the response of the studied rock along a tensile loading followed by an unloading and a reloading in compression is provided in order to illustrate the so-called unilateral damage effects due to microcracks closure.

Mots clés: Anisotropic rocks; Damage-induced anisotropy; Microcracks closure effects; Homogenization and micromechanics; Argillite

Domaines: Mécanique des matériaux [physics.class-ph]

Séverine Levasseur, Hélène Welemane, Djimédo Kondo. A microcracks-induced damage model for initially anisotropic rocks accounting for microcracks closure. International Journal of Rock Mechanics and Mining Sciences, 2015, vol. 77, pp. 122-132. ⟨10.1016/j.ijrmms.2015.03.011⟩. ⟨hal-01212103⟩